Beryllium (4Be) has 11 known isotopes and 3 known isomers, but only one of these isotopes (9Be) is stable and a primordial nuclide. As such, beryllium is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes have such short half-lives that none are primordial and their abundance is very low. Beryllium is unique as being the only monoisotopic element with an even number of protons (even atomic number) and also has an odd number of neutrons;[2] the 25 other monoisotopic elements all have odd numbers of protons (odd atomic number), and even of neutrons, so the total mass number is still odd.
Of the 10 radioisotopes of beryllium, the most stable are 10Be with a half-life of 1.387million years and 7Be with a half-life of 53.22 days. All other radioisotopes have half-lives shorter than 15 seconds.
The 1:1 neutron–proton ratio seen in stable isotopes of many light elements (up to oxygen, and in elements with even atomic number up to calcium) is prevented in beryllium by the extreme instability of 8Be toward splitting into two 4He nuclei, which may be seen either alpha decay or a type of fission; in any case the half-life is only 8.2×10−17s, short enough to normally be considered unbound. This, as with the relative instability of all lithium, beryllium, and boron isotopes, is favored due to the extremely tight binding of the helium-4 nucleus.
Beryllium is prevented from having a stable isotope with 4 protons and 6 neutrons by the very lopsided neutron–proton ratio for such a light element. Nevertheless, this isotope, beryllium-10, has a half-life above a million years and a decay energy less than 1 MeV, which indicates unusual stability given that condition.
Most beryllium present in the universe is thought to be formed by cosmic ray nucleosynthesis from cosmic ray spallation in the period between the Big Bang and the formation of the Solar System. The isotopes 7Be and 10ベリリウムとベリリウムはどちらも宇宙線生成核種です。なぜなら、太陽系では核破砕によって継続的に生成されるからです。[ 4 ]炭素14も同様です。
1 2 3 4 Kondev, FG; Wang, M.; Huang, WJ; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF) . Chinese Physics C . 45 (3) 030001. doi : 10.1088/1674-1137/abddae .
↑ J. Beer; K. McCracken; R. von Steiger (2012).宇宙線生成放射性核種：地球および宇宙環境における理論と応用. 地球および宇宙環境の物理学. 第26巻. 地球および宇宙環境の物理学, Springer, Berlin. doi : 10.1007/978-3-642-14651-0 . ISBN978-3-642-14650-3. S2CID 55739885 .
↑ Balco, Greg; Shuster, David L. (2009). " 26 Al- 10 Be– 21 Ne 埋葬年代測定" (PDF) . Earth and Planetary Science Letters . 286 ( 3– 4): 570– 575. Bibcode : 2009E & PSL.286..570B . doi : 10.1016/j.epsl.2009.07.025 . 2015-09-23 のオリジナル(PDF)からアーカイブ済み。2012-12-10に取得。
↑ Paleari, Chiara I.; F. Mekhaldi; F. Adolphi; M. Christl; C. Vockenhuber; P. Gautschi; J. Beer; N. Brehm; T. Erhardt; H.-A. Synal; L. Wacker; F. Wilhelms; R. Muscheler (2022). "宇宙線生成放射性核種が9125年前の太陽活動極小期付近の極端な太陽粒子嵐を明らかにする" . Nat. Commun . 13 (214): 214. Bibcode : 2022NatCo..13..214P . doi : 10.1038/s41467-021-27891-4 . PMC 8752676 . PMID 35017519 .
↑ Philip Ball (2001年12月19日)「ちらつく太陽が気候を変えた」Nature . doi : 10.1038/news011220-9 .
![{\displaystyle {\begin{array}{l}{}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {6}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {6}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[5\ \mathrm {zs} ]~{\mathrm {^{4}_{2}彼} }{}+{}{\mathrm {2_{1}^{1}H} }}\\{{\mathrm {^{7}_{4}Be} }{}+{}\mathrm {e} {\vphantom {A}}^{-}{}\mathrel {\longrightarrow } {}[53.22\ \mathrm {d} ]~{\mathrm {^{7}_{3}Li} }}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {8}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {8}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[81.9\ \mathrm {as} ]~{\mathrm {2_{2}^{4}He} }}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {10}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {10}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[1.387\ \mathrm {Ma} ]~{\mathrm {^{10}_{5}B} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {11}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {11}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[13.76\ \mathrm {s} ]~{\mathrm {^{11}_{5}B} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {11}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {11}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[13.76\ \mathrm {s} ]~{\mathrm {^{7}_{3}李} }{}+{}{\mathrm {^{4}_{2}彼} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {12}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {12}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[21.46\ \mathrm {ms} ]~{\mathrm {^{12}_{5}B} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {12}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {12}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[21.46\ \mathrm {ms} ]~{\mathrm {^{11}_{5}B} }{}+{}{\mathrm {^{1}_{0}n} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {13}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {13}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[1\ \mathrm {zs} ]~{\mathrm {^{12}_{4}Be} }{}+{}{\mathrm {^{1}_{0}n} }}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {14}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {14}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[4.53\ \mathrm {ms} ]~{\mathrm {^{13}_{5}B} }{}+{}{\mathrm {^{1}_{0}n} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {14}}{\mkern {-1。5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {14}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[4.53\ \mathrm {ms} ]~{\mathrm {^{14}_{5}B} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {14}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {14}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[4.53\ \mathrm {ms} ]~{\mathrm {^{12}_{5}B} }{}+{}{\mathrm {2_{0}^{1}n} }{}+{}\mathrm {e} {\vphantom {A}}^{-}}\\{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {15}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {15}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[790\ \mathrm {ys} ]~{\mathrm {^{14}_{4}Be} }{}+{}{\mathrm {^{1}_{0}n} }}\\{}{{\vphantom {A}}_{\hphantom {4}}^{\hphantom {16}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{4}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {16}}}\mathrm {Be} {}\mathrel {\longrightarrow } {}[650\ \mathrm {ys} ]~{\mathrm {^{14}_{4}Be} }{}+{}{\mathrm {2_{0}^{1}n} }}\\{}\end{array}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/a497c0c3df361fb9d2c670e9871797b5a61b4615)